My brother sold his 6-year-old Mazda 3 and got a good trade-in value by knowing the car's condition and having maintenance records. There are several tips for getting the best value when selling a car: know the car's full history and condition, decide whether to trade it in or sell privately, clean and repair any issues, set an appropriate asking price based on mileage and condition, and use maintenance records to justify the price. Following these tips can help drivers get the best deal.